The venerable puppets of Sesame Street have gone through many iterations throughout the years — don't forget that Mr. Snuffleupagus was pretty unsettling in his first appearance. And before characters like Big Bird and Cookie Monster made it to the screen, they were but mere scribbles in Jim Henson's notebook.

Clockwise from the top-left, that's Cookie Monster (who began his career as a corporate spokesmonster in the 1960s), a chicken-like Big Bird, early Elmo, the antecedents of Ernie and Bert, and "the Gourmet Bird" from a never-filmed Stouffer's Food television spot, who served as a proto-Big Bird of sorts. (Click on the above image to expand.)